psk-crack man page

psk-crack — Crack IKE Aggressive Mode Pre-Shared Keys


psk-crack [options] <psk-parameters-file>

<psk-parameters-file> is a file containing the parameters for the pre-shared key cracking process in the format generated by ike-scan with the --pskcrack (-P) option.  This file can contain one or more entries.  For multiple entries, each one must be on a separate line.

The program can crack either MD5 or SHA1-based hashes.  The type of hash is automatically determined from the length of the hash (16 bytes for MD5 or 20 bytes for SHA1).  Each entry in the <psk-parameters-file> is handled separately, so it is possible to crack a mixture of MD5 and SHA1 hashes.

psk-crack can also crack the proprietary hash format used by Nortel Contivity / VPN Router systems.  When cracking Nortel format hashes, you need to specify the username of the hash that you are cracking with the --norteluser (-u) option.  When cracking Nortel format hashes, you can only crack one hash at a time.

By default, psk-crack will perform dictionary cracking using the default dictionary.  The dictionary can be changed with the --dictionary (-d) option, or brute-force cracking can be selected with the --bruteforce (-B) option.


psk-crack attempts to crack IKE Aggressive Mode pre-shared keys that have previously been gathered using ike-scan with the --pskcrack option.

psk-crack can operate in two different modes:


Dictionary cracking mode: this is the default mode in which psk-crack tries each candidate word from the dictionary file in turn until it finds a match, or all the words in the dictionary have been tried.


Brute-force cracking mode: in this mode, psk-crack tries all possible combinations of a specified character set up to a given length.


--help or -h

Display this usage message and exit.

--version or -V

Display program version and exit.

--verbose or -v

Display verbose progress messages.

--dictionary=<f> or -d <f>

Set dictionary file to <f>.  The default is /usr/local/share/ike-scan/psk-crack-dictionary.

--norteluser=<u> or -u <u>

Specify the username for Nortel Contivity cracking. This option is required when cracking pre-shared keys on Nortel Contivity / VPN Router systems.  These systems use a proprietary method to calculate the hash that includes the username. This option is only needed when cracking Nortel format hashes, and should not be used for standard format hashes.

--bruteforce=<n> or -B <n>

Select bruteforce cracking up to <n> characters.

--charset=<s> or -c <s>

Set bruteforce character set to <s> Default is "0123456789abcdefghijklmnopqrstuvwxyz"


Roy Hills <>


February 14, 2005